docs: def is_installed(self, name: str) -> bool:
          """
          Indicates a given Docker image is installed on this server.
  
          Parameters:
              name: the name of the Docker image.
  
          Returns:
              `True` if installed; `False` if not.
          """
          assert name is not None
          try:
              self.__docker.images.get(name)
              return True
          except docker.errors.ImageNotFound:
              return False